Mimo Channel Feedback Protocols

1. A method comprising: receiving a first wireless frame from a first wireless entity at a second wireless entity through a multiple input, multiple output (MIMO) channel, said first wireless frame including channel training data; determining channel information for said MIMO channel using said channel training data; determining a data rate for said first wireless entity to use to transmit user data to said second wireless entity in a subsequent data frame based on said channel information; determining, based on said data rate, a network allocation vector (NAV) to indicate a time period during which a wireless medium is to be reserved to accommodate transmission of said subsequent data frame of said first wireless entity; and transmitting a second wireless frame from said second wireless entity to said first wireless entity, said second wireless frame including said NAV.

2. The method of claim 1 , wherein: said channel training data includes per antenna training data from each of a plurality of antennas associated with said first wireless entity.

3. The method of claim 1 , wherein: said second wireless frame further includes channel related feedback information.

4. The method of claim 1 , wherein: said first wireless entity is a wireless access point and said second wireless entity is a wireless station.

5. The method of claim 1 , wherein: said first wireless entity is a wireless station and said second wireless entity is a wireless access point.

6. The method of claim 1 , wherein: determining channel information for said MIMO channel includes generating a channel matrix H for said MIMO channel.

7. The method of claim 6 , wherein: determining channel information for said MIMO channel includes performing a singular value decomposition (SVD) of said channel matrix H.

8. The method of claim 1 , wherein: determining a NAV includes determining a duration of a user data portion of said subsequent data frame by multiplying an amount of data by said data rate.

9. The method of claim 1 , wherein: said first wireless frame is a training initiation frame and said second wireless frame is a training response frame.

10. The method of claim 9 , wherein: said training initiation frame includes another NAV to indicate a time period during which the wireless medium is to be reserved to accommodate transmission of said training response frame.

11. The method of claim 1 , further comprising: receiving said subsequent data frame from said first wireless entity and transmitting an ACK frame to said first wireless entity to indicate that said subsequent data frame has been successfully received.

12. The method of claim 11 , wherein: said subsequent data frame includes another NAV to indicate a time period during which the wireless medium is to be reserved to accommodate transmission of said ACK frame.

13. An apparatus comprising: a wireless transceiver; and a controller coupled to said wireless transceiver, said controller being operative to: obtain channel training data that was received from a remote wireless entity through a multiple input, multiple output (MIMO) channel; determine channel information for said MIMO channel using said channel training data; determine a data rate for said remote wireless entity to use to transmit user data to said apparatus in a subsequent data frame based on said channel information; determine, based on said data rate, a network allocation vector (NAV) to indicate a time period during which a wireless medium is to be reserved to accommodate transmission of said subsequent data frame of said remote wireless entity; and cause a wireless frame to be transmitted to said remote wireless entity by said wireless transceiver, said wireless frame including said NAV.

14. The apparatus of claim 13 , wherein: said channel training data includes per antenna training data received from each of a plurality of antennas associated with said remote wireless entity.

15. The apparatus of claim 13 , wherein: said wireless frame includes channel related feedback information.

16. The apparatus of claim 13 , wherein: said controller is operative to receive said subsequent data frame from said remote wireless entity and cause an ACK frame to be transmitted to said remote wireless entity by said wireless transceiver to indicate that said subsequent data frame has been successfully received.

17. A system comprising: at least two dipole antennas; a wireless transceiver coupled to said at least two dipole antennas; and a controller coupled to said wireless transceiver, said controller being operative to: obtain channel training data that was received from a remote wireless entity through a multiple input, multiple output (MIMO) channel; determine channel information for said MIMO channel using said channel training data; determine a data rate for said remote wireless entity to use to transmit user data to said system in a subsequent data frame based on said channel information; determine, based on said data rate, a network allocation vector (NAV) to indicate a time period during which a wireless medium is to be reserved to accommodate transmission of said subsequent data frame of said remote wireless entity; and cause a wireless frame to be transmitted to said remote wireless entity by said wireless transceiver, said wireless frame including said NAV.

18. The system of claim 17 , wherein: said system is a wireless access point.

19. The system of claim 17 , wherein: said system is a wireless network station.

20. The system of claim 17 , wherein: said wireless frame includes channel related feedback information.

21. The system of claim 17 , wherein: said controller is operative to receive said subsequent data frame from said remote wireless entity and cause an ACK frame to be transmitted to said remote wireless entity by said wireless transceiver to indicate that said subsequent data frame has been successfully received.

22. An article comprising a computer readable storage medium having computer executable instructions stored thereon that, when executed by a computing platform, operate to: obtain channel training data that was received from a remote wireless entity through a multiple input, multiple output (MIMO) channel; determine channel information for said MIMO channel using said channel training data; determine a data rate for said remote wireless entity to use to transmit user data in a subsequent data frame based on said channel information; determine, based on said data rate, a network allocation vector (NAV) to indicate a time period during which a wireless medium is to be reserved to accommodate transmission of said subsequent data frame of said remote wireless entity; and cause a wireless frame to be transmitted to said remote wireless entity, said wireless frame including said NAV.

23. The article of claim 22 , wherein: said channel training data includes per antenna training data received from each of a plurality of antennas associated with said remote wireless entity.

24. The article of claim 22 , wherein: said wireless frame includes channel related feedback information.

25. The article of claim 22 , wherein said instructions further operate to: receive said subsequent data frame from said remote wireless entity and cause an ACK frame to be transmitted to said remote wireless entity to indicate that said subsequent data frame has been successfully received.

26. A method for use during a wireless frame exchange, comprising: first determining whether a MIMO channel between a first wireless entity and a second wireless entity is drifting; and second determining whether to include additional per stream training data within a data frame to be transmitted from said first wireless entity to said second wireless entity based on whether said MIMO channel is drifting, wherein said additional per stream training data is training data for one or more spatial channels of said MIMO channel that are different from spatial channels selected by said second wireless entity.

27. The method of claim 26 , wherein: first and second determining are performed at said first wireless entity.

28. The method of claim 26 , wherein: first and second determining are performed at said second wireless entity.

29. The method of claim 28 , further comprising: calculating a network allocation vector (NAV), at said second wireless entity, to reserve a network medium until an end of said data frame to be transmitted from said first wireless entity, wherein calculating a NAV includes considering whether additional per stream training data will be included within said data frame.

30. The method of claim 26 , wherein: second determining comprises including additional per stream training data within said data frame by default unless said MIMO channel is not drifting.

31. The method of claim 26 , wherein: second determining comprises not including additional per stream training data within said data frame by default unless said MIMO channel is drifting.

32. The method of claim 26 , further comprising: first determining includes monitoring a past history of said MIMO channel.

33. The method of claim 26 , wherein: first determining includes determining whether said MIMO channel meets a predetermined drift criterion.

34. The method of claim 26 , wherein: said first wireless entity is a wireless access point and said second wireless entity is a wireless station.

35. The method of claim 26 , wherein: said first wireless entity is a wireless station and said second wireless entity is a wireless access point.